Catalytic conversion over membrane composed of a pure molecular sieve

ABSTRACT

A process is provided for catalytic conversion of organic compounds in a conversion zone containing a synthetic, non-composited microporous membrane comprising a continuous array of crystalline molecular sieve material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 533,328, filedJun. 5, 1990, now U.S. Pat. No. 5,019,263.

BACKGROUND OF THE INVENTION

The present invention relates use of membranes having molecular sieveproperties and/or catalytic activity in a process for organic compound,e.g. hydrocarbon compound, alcohol or ether, conversion.

Membrane separation technology is a rapidly expanding field. Organic andinorganic materials have been used as membranes in a variety ofseparation processes, such as microfiltration, ultrafiltration,dialysis, electrodialysis, reverse osmosis and gas permeation. Mostmembranes have been made from organic polymers with pore sizes rangingfrom 10 to 1000 angstroms. Membranes have also been made from inorganicmaterials such as ceramics, metals, clay and glasses.

Synthetic zeolites have been used as adsorptive separation agents forgases or liquids or as catalysts and have usually been used in the formof granules or pellets often incorporated with a binder such as clay oralumina. The potential of zeolites as components in microporousmembranes has not been fully explored.

Zeolites have also been used as components in composite membranes. Insuch membranes, in addition to the presence of a zeolite phase, themembrane material always contains a second phase with distinctlydifferent chemical composition, physical properties, chemical propertiesand morphology. As a result of the presence of different phases, theseparation properties of composite membranes are determined by theindividual properties of the different phases and of the phaseboundaries. (Demertzes et al., J. Chem. Soc., Faraday Trans. 1, 82, 3647(1986)). Examples of such non-zeolitic phases are polymeric materialsand inorganic materials such as glasses, silica or alumina.

Composite membranes or filters of materials such as paper and polymerswhich may contain dispersed particles of zeolites have been described,for example, in U.S. Pat. Nos. 3,266,973; 3,791,969; 4,012,206;4,735,193; 4,740,219 and European Patent Application 254758.

U.S. Pat. No. 4,699,892 describes a composite membrane having anultrathin film of a cage-shaped zeolite of from 10 to several hundredangstroms in thickness on a porous support of metal, inorganic materialor polymeric material.

Non-composited inorganic membranes are described, for example, in U.S.Pat. Nos. 3,392,103; 3,499,537; 3,628,669 and 3,791,969.

U.S. Pat. No. 3,392,103 describes membranes made from hydrous metaloxide ceramics such as aluminum oxide. U.S. Pat. No. 3,499,537 disclosesmembranes of pressed and sintered aluminum vanadate powder. U.S. Pat.No. 3,628,669 discloses silica membranes made by leaching thin inorganicglass films. U.S. Pat. No. 3,791,969 describes membranes of flocculatedsodium exfoliated vermiculite.

Other non-composited membranes described in U.S. Pat. Nos. 3,413,219 and4,238,590 require some manner of supporting material. U.S. Pat. No.3,413,219 discloses the preparation of membranes from colloidal hydrousoxide which is formed on a permeable substrate. U.S. Pat. No. 4,238,590discloses silicic acid heteropolycondensates suitable for use asmembranes but which are not self-supporting and are stretched overporous or net-like supporting material.

It is therefore an object of the invention to provide a pure andspatially continuous molecular sieve membrane for use in catalyticconversion of organic compounds. It is also an object to provide amaterial of macroscopic dimensions, composed only of a zeolitic phase,and having adequate mechanical strength to maintain its macroscopicstructural integrity and capable of carrying out molecular sieve action.

SUMMARY OF THE INVENTION

The present invention comprises a process for converting feedstockcomprising organic compounds, e.g. hydrocarbons or oxygenates, tocoversion product by contacting said feedstock with a synthetic,non-composited, microporous membrane comprising a continuous array ofcrystalline molecular sieve material. The molecular sieve may have acomposition in terms of mole ratios of oxides as follows:

    X.sub.2 O.sub.3 : (n)YO.sub.2

wherein X is a trivalent element of at least one member selected fromthe group consisting of aluminum, boron, iron and gallium; Y is atetravalent element of at least one member selected from the groupconsisting of silicon, germanium and titanium; and, n is at least about2.

The crystalline material may also be an aluminophosphate,silicoaluminophosphate, metaloaluminophosphate ormetaloaluminophosphosilicate.

In the method for preparing the microporous membrane, a chemical mixturecapable of forming the crystalline molecular sieve material is preparedand the mixture is formed into a thin, uncomposited, cohesive,continuous membrane, dried and calcined.

A method is also provided for using the membrane for the separation ofthe components of a gaseous or liquid mixture having at least twocomponents. The mixture is contacted with an upstream face of themembrane under separation conditions such that at least one component ofthe mixture has a greater steady state permeability through the membranethan at least one of the remaining component(s) of the mixture. Aftercontact of the mixture with the membrane and passage through themembrane, the component with the greater permeability is collected onthe downstream side of the membrane.

The present process comprises using the membrane as a catalyst. Themembrane is rendered catalytically active and a feedstock is passedthrough the upstream face of the membrane under catalytic conditions.For cases where all or at least one of the reaction products have higherpermeability than the reactant(s), they will emerge from the downstreamside of the membrane. In equilibrium limited reactions, this will leadto higher single-pass conversion of the reactant(s) than normallyobserved and allowed by thermodynamic equilibrium constraints. At leastone or all of the reaction products are collected on the downstream sideof the membrane. Other advantages can be realized, for example, when oneor all of the products inhibit or poison the desired reaction, or whenthey would undergo undesired secondary reactions.

The microporous zeolitic membranes prepared for use hereinadvantageously have unique molecular sieve and/or catalytic propertiesdue to the well defined pore structure of zeolites. The membranes havethe advantages of having different properties from traditionally usedgranular form zeolites, and from composited membranes which includezeolites. These different properties result from the sheet-likestructure of the membranes and the composition of pure zeolite in themembrane.

For a better understanding of the present invention, together with otherand further objects, reference is made to the following description,taken together with the accompanying drawings, and its scope will bepointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of a Si-NMR spectrum of the crystalline membrane.

FIG. 2a shows the membrane surface which was exposed to the non-poroussubstrate during crystallization.

FIG. 2b shows the membrane surface which was exposed to the synthesismixture.

FIG. 2c shows crystal intergrowth on the surface of a large singlecrystal.

FIG. 2d is a higher magnification of the view of FIG. 2c.

FIG. 3 illustrates the membrane affixed in a Wicke-Kallenbach cell.

DETAILED DESCRIPTION OF THE INVENTION

Zeolite materials, both natural and synthetic, have been demonstrated inthe past to have catalytic properties of various types of hydrocarbonconversion. Certain zeolitic materials are ordered, porous, crystallinealuminosilicates having a definite crystalline structure as determinedby X-ray diffraction, within which there are a large number of smallercavities and channels or pores. These cavities and pores are uniform insize within a specific zeolitic material. Since the dimensions of thesepores are such as to accept for adsorption molecules of certaindimensions while rejecting those of larger dimensions, these materialshave come to be known as "molecular sieves" and are utilized in avariety of ways to take advantage of these properties.

Zeolites typically have uniform pore diameters of about 3 angstroms toabout 10 angstroms. The chemical composition of zeolites can vary widelyand they typically consist of SiO₂ in which some of the silicon atomsmay be replaced by tetravalent ions such as Ti or Ge, by trivalent ionssuch as Al, B, Ga, Fe, or by bivalent ions such as Be, or by acombination of any of the aforementioned ions. When there issubstitution by bivalent or trivalent ions, cations such as Na, K, Ca,NH₄ or H are also present.

Representative examples of siliceous zeolites are small pore zeolitessuch as NaA, CaA, Erionite; medium pore zeolites such as ZSM-5, ZSM-11,ZSM-22, ZSM-23, ZSM-48, ZSM-12, zeolite beta; and large pore zeolitessuch as zeolite L, ZSM-4 (omega), NaX, NaY, CaY, REY, US-Y, ZSM-20, andmordenite.

Zeolites include a wide variety of positive ion-containing crystallinealuminosilicates. These aluminosilicates can be described as a rigidthree-dimensional framework of SiO₄ and AlO₄ in which the tetrahedra arecross-linked by the sharing of oxygen atoms whereby the ratio of thetotal aluminum and silicon atoms to oxygen atoms is 1:2. Theelectrovalence of the tetrahedra containing aluminum is balanced by theinclusion in the crystal of the cation, for example an alkali metal oran alkaline earth metal cation. This can be expressed wherein the ratioof aluminum to the number of various cations, such as Ca/2, Sr/2, Na, Kor Li, is equal to unity. One type of cation may be exchanged eitherentirely or partially with another type of cation utilizing ion exchangetechniques in a conventional manner. By means of such cation exchange,it has been possible to vary the properties of a given aluminosilicateby suitable selection of the cation. The spaces between the tetrahedraare occupied by molecules of water prior to dehydration.

Prior art techniques have resulted in the formation of a great varietyof synthetic zeolites. The zeolites have come to be designated by letteror other convenient symbols, as illustrated by zeolite A (U.S. Pat. No.2,882,243); zeolite X (U.S. Pat. No. 2,882,244); zeolite Y (U.S. Pat.No. 3,130,007); zeolite beta (U.S. Pat. No. 3,308,069); zeolite ZK-5(U.S. Pat. No. 3,247,195); zeolite ZK-4 (U.S. Pat. No. 3,314,752);zeolite ZSM-5 (U.S. Pat. No. 3,702,886); ZSM-5/ZSM-ll intermediate (U.S.Pat. No. 4,229,424); zeolite ZSM-23 (U.S. Pat. No. 4,076,842); zeoliteZSM-11 (U.S. Pat. No. 3,709,979); zeolite ZSM-12 (U.S. Pat. No.3,832,449); zeolite ZSM-20 (U.S. Pat. No. 3,972,983); ZSM-35 (U.S. Pat.No. 4,016,245), ZSM-38 (U.S. Pat. No. 4,046,859); and zeolite ZSM-48(U.S. Pat. No. 4,375,573), merely to name a few. All of the abovepatents are incorporated herein by reference.

The silicon/aluminum atomic ratio of a given zeolite is often variable.For example, zeolite X can be synthesized with silicon/aluminum atomicratios of from 1 to 1.5; zeolite Y, from 1.5 to about 3. In somezeolites, the upper limit of the silicon/aluminum atomic ratio isunbounded. ZSM-5 is one such example wherein the silicon/aluminum atomicratio is at least 12. U.S. Pat. No. 3,941,871 (Re. 29,948) discloses aporous crystalline silicate made from a reaction mixture containing nodeliberately added aluminum in the recipe and exhibiting the X-raydiffraction pattern characteristic of ZSM-5 type zeolites. U.S. Pat.Nos. 4,061,724; 4,073,865 and 4,104,294 describe crystalline silicas ofvarying aluminum and metal content. These zeolites can consistessentially of silica, containing only trace amounts of aluminum.

Another class of molecular sieves consists of AlO₂ and PO₂ units (AlPO₄)whose Al or P constituents optionally may be substituted by otherelements such as Si (called silicoaluminophosphates or SAPO's), ormetals (called metaloaluminophosphates or MeAPO's) or combinationsthereof (called metaloaluminophosphosilicates or MeAPSO's). As withaluminosilicates, the ALPO 's, SAPO's, MeAPO's and MeAPSO's arecrystalline and have ordered pore structures which accept certainmolecules while rejecting others and they are often considered to bezeolitic materials.

Aluminum phosphates are taught in U.S. Pat. Nos. 4,310,440 and 4,385,994for example. These aluminum phosphate materials have essentiallyelectroneutral lattices. U.S. Pat. No. 3,801,704 teaches an aluminumphosphate treated in a certain way to impart acidity.

The crystalline silicoaluminophosphates useful for the membranes of theinvention have molecular sieve framework which may exhibit ion-exchangeproperties and may be converted to material having intrinsic catalyticactivity.

Silicoaluminophosphates of various structures are taught in U.S. Pat.No. 4,440,871. Aluminosilicates containing phosphorous, i.e.silicoaluminophosphates of particular structures are taught in U.S. Pat.Nos. 3,355,246 (i.e. ZK-21) and 3,791,964 (i.e. ZK-22). Other teachingsof silicoaluminophosphates and their synthesis include U.S. Pat. Nos.4,673,559 (two-phase synthesis method); 4,623,527 (MCM-10); 4,639,358(MCM-1); 4,647,442 (MCM-2); 4,664,897 (MCM-4); 4,638,357 (MCM-5) and4,632,811 (MCM-3). All of the above patents are incorporated herein byreference.

A method for synthesizing crystalline metaloaluminophosphates (MeAPO's)is shown in U.S. Pat. No. 4,713,227, and an antimonophosphoaluminate andthe method for its synthesis are taught in U.S. Pat. No. 4,619,818. U.S.Pat. No. 4,567,029 teaches metalloaluminophosphates, andtitaniumaluminophosphate and the method for its synthesis are taught inU.S. Patent No. 4,500,651.

Compositions comprising crystals having a framework topology afterheating at 110° C. or higher giving an X-ray diffraction patternindicating pore windows formed by 18 tetrahedral members of about 12-13Angstroms in diameter are taught in U.S. Pat. No. 4,880,611,incorporated herein by reference.

The membranes for use in the invention consist essentially of onlymolecular sieve material, as contrasted with prior art compositemembranes which can contain various amounts of molecular sieve materialcomposited with other materials. The zeolitic membrane may contain asingle zeolite or mixtures of zeolites. The membrane can bemonocrystalline or polycrystalline. "Monocrystalline" is intended tomean consisting of a single crystal. "Polycrystalline" is intended tomean consisting of a continuous intergrowth of more than a singlecrystal, e.g. many crystals.

The membrane can be produced, for example, by synthesis underhydrothermal conditions on a non-porous substrate forming surface, suchas a polymer, a metal or glass. Suitable polymer surfaces are, forexample, fluorocarbon polymers such as tetrafluoroethylene (TFE) andfluorinated ethylene-propylene polymers (FEP). Suitable metal surfacesare, for example, silver, nickel, aluminum and stainless steel. A thinlayer of metal on glass or an organic polymer or other material may beused as the forming surface. A thin layer of a polymer film on glass orother material may also be used as the forming surface. The formingsurface may have various configurations. For example, the surface may beflat, curved, a hollow cylinder or honeycomb-shaped.

Although amorphous materials can be used as substrates for crystalgrowth, monocrystalline surfaces can also be used. The synthesis canalso be achieved by mechanical compression of a powder form zeolite,followed by chemical treatment.

In forming the membranes for use in the invention, a non-porous surfaceis contacted with a chemical mixture capable of forming the desiredcrystalline material under crystallization conditions. After a period oftime under suitable conditions, a cohesive membrane of crystallizedmaterial forms on the non-porous substrate surface. The thicknessdimension of the membrane may vary from about 0.1 micron to about 400microns depending upon the length of time the surface is contacted withthe chemical mixture and the amount of mixture provided. Other meanssuch as varying the temperature or the ratio of crystallization mixtureto forming surface area are also effective in adjusting the membranethickness to a desired dimension.

The chemical composition of the forming mixture, in terms of moles permole YO₂, includes:

    ______________________________________                                                                     Most                                                      Broad   Preferred   Preferred                                        ______________________________________                                        H.sub.2 O/YO.sub.2                                                                       5 to 500  >20 to 500  >40 to 500                                   X.sub.2 O.sub.3 /YO.sub.2                                                                0 to 0.2    0 to 0.014                                                                                0 to 0.010                                 OH.sup.- /YO.sub.2                                                                       0 to 2     0.02 to 0.15                                                                              0.02 to 0.15                                ______________________________________                                    

In general, preferred forming mixture compositions are those combining ahigh H₂ O/YO₂ ratio (towards the upper end of the indicated range), alow X₂ O ratio and a low OH⁻ /YO₂ ratio. Also microporous crystals witha tendency to form twinned crystals are particularly prone to formmembranes.

To form membrane film of uniform thickness and avoid homogeneouscrystallization, a minimum H₂ O/YO₂ ratio is preferred, which depends onthe X₂ O ratio. This minimum ratio is about 20 for X₂ O₃ /YO₂ ≦0.0025,70 for X₂ O₃ /YO₂ =0.01 and 130 for X₂ O₃ YO₂ =0.014.

For crystallizing a membrane having the structure of ZSM-5, for example,it is preferred to use an organic matrix such as tetrapropylammonium(TPA) in a ratio TPA/YO₂ of 0-2, preferably 0.05-1. Other well-knownorganic matrices can be used for the syntheses of other zeolitemembranes.

The method of synthesis can be either in a batch process, semicontinuousor continuous process. In a batch process, it is preferred to use staticconditions, i.e. absence of stirring, to promote formation of amembrane. In a continuous or semicontinuous process, a forming solutionor slurry is passed through the reaction zone with or without recycle.In the recycle mode, the composition of the solution can be adjusted andmaintained at optimal concentrations. This mode of operation isparticularly advantageous when very high H₂ O/YO₂ ratios are employed.

The thickness of the membrane can be controlled by varying thecrystallization time or by adjusting the total nutrient (e.g. SiO2)provided per surface area of the membrane-forming surface.

The time of contacting of the surface with the reaction mixture may befrom about 0 5 hrs. to about 1000 hrs., preferably from about 1 hr. toabout 100 hrs.; at a temperature of from about 50° C. to about 250° C.,preferably from about 110° C. to about 200° C.; and at a pressure fromabout 1 atm to about 100 atm, preferably from about 1 atm to about 15atm.

After the desired period of time, the substrate, now coated withcrystalline material, is removed from contact with the chemical mixture,washed with distilled water and allowed to dry.

The layer of crystalline material may be removed from the non-poroussurface by various means depending upon the material chosen for theforming surface. The layer may be separated from polymeric surfaces, forexample, by mechanical means such as careful scraping or peeling.Removal from metal surfaces may be accomplished with the use of solventssuch as acetone, or by dissolving the metal with acid such as aqueoushydrochloric or nitric acid. With a support consisting of metal ormetallized material such as aluminum on glass or teflon, treatment withan aqueous mineral acid can be employed.

The membrane material may also be calcined before or after removal fromthe substrate for example in an inert atmosphere or in air at from about200 to about 700° C. for about 1 hr. to about 50 hrs.

The membrane may also be treated to adjust its catalytic propertiesbefore or after removal from the surface, for example by steaming and/orion exchange. Low or zero catalytic activity can be obtained byincorporating alkali or alkaline earth cations into the membrane.

Catalytic activity can be increased by methods known in the art such asby increasing the aluminum content or by introducing ahydrogenation-dehydrogenation function into the membrane.

The original ions, i.e. cations or anions, of the synthesized membranecan be replaced in accordance with techniques well known in the art, atleast in part, by ion exchange with other cations or anions. Preferredreplacing cations include metal ions, hydrogen ions, hydrogen precursor,e.g. ammonium ions and mixtures thereof Particularly preferred cationsinclude hydrogen, rare earth metals and metals of Groups IIA, IIIA, IVA,IB, IIB, IIIB, IVB, VIB and VIII of the Periodic Table of the Elements.

Typical ion exchange technique would be to contact the synthesizedmembrane with a salt of the desired replacing ion or ions. Examples ofsuch salts of cations include the halides, e.g., chlorides, nitrates andsulfates.

Cations may be incorporated into the membrane to neutralize acid sitesor to adjust the diffusion properties; preferred cations to beincorporated for these purposes include metals of Groups IA and IIA ofthe Periodic Table of the Elements, for example, sodium, potassium,magnesium, barium, lithium, strontium, rubidium and cesium.

Siliceous membranes containing a relatively high concentration ofaluminum (SiO₂ /Al₂ O₃ <100) can be prepared directly by synthesis.Alternatively, a high SiO₂ /Al₂ O₃ membrane can be prepared first andaluminum incorporated by post-synthesis treatment, using known methods,e.g. treatment with reactive aluminum compounds such as AlCl₃ atelevated temperature; by adding aluminum oxide or hydroxide andtreatment under hydrothermal conditions; or by treating with smallamounts of sodium aluminate.

Other metals can be incorporated during synthesis (e.g. titanium, tin,iron, gallium, transition metals) or post-synthetically via knownprocesses such as impregnation, ion exchange, vapor deposition and thelike.

The diffusive properties of the membrane such as permeation rate andselectivity, depend on the geometric properties, particularly thethickness, and the particular zeolite that constitutes the membrane. Agiven membrane can be further modified by subsequent treatment thatchanges the diffusion properties. Examples of such treatments are:deposition of coke or organic compounds, such as pyridine or othercarbonaceous material, at the exterior or interior of the zeolite pores,deposition of silica or silicon compounds via treatment with SiCl₄ orSi(OR)₄ followed by calcination, treatment with phosphorus compounds,incorporation of metal salts or oxides, such as of Mg, Mo, W, Sb, orother oxides such as silicon dioxide, or ion exchange, e.g., with K, Rb,Cs, or Ag.

It is also contemplated that a metal function can be incorporated intothe membrane, such as Pd, Pt, Ru, Mo, W, Ni, Fe, Ag, etc. Thesemetal-containing membranes may have essentially no acid activity, orthey may have substantial acid activity to provide for dual-functionalcatalysis. The catalytic activity of the membrane can be adjusted fromessentially zero to high activity, depending on the particular usethereof.

The membranes can be used for separation of gaseous or liquid mixturesor catalytic applications which combine chemical conversion of thereactant with in situ separation of the products.

A variety of gaseous or liquid mixtures may be separated using themembrane. Examples of mixtures advantageously separated are oxygen andnitrogen, hydrogen and carbon monoxide, linear and branched paraffins,hydrogen and methane, p-xylene and m- and/or o-xylene.

Further examples of desirable separations to be carried out with themembranes described herein include: (1) removal of waxy components fromdistillate and lube oil fractions and of linear and slightly branchedparaffins from mixtures such as reformate; (2) removal of organics fromaqueous streams in which high silica (SiO₂ /Al₂ O₃ ≦100) microporousmaterials are particularly useful; examples include removal of ethanolfrom fermentation mixtures used to produce beer or wine and removal ofharmful organic contaminants from ground water or waste streams; and (3)removal of paraffins from aromatics using a high silica zeolitemembrane, and aromatics from paraffins, using low SiO₂ Al₂ O₃ zeolitemembrane in the alkali-exchanged form.

When separation of the components of a gaseous or liquid mixture is tobe accomplished, a low or zero activity zeolitic membrane is preferablyused. Siliceous zeolites of low or zero activity contain no or onlytrace amounts of two-or three-valent metal ions; or when they containsubstantial amount of such ions, their catalytic activity can be reducedto the desired low level by cation exchange with alkali or alkalineearth cations, by thermal or steam treatment, by treatment withphosphorus compounds and steaming, or by replacement of the three-valentions, e.g., Al, by four-valent ions, e.g., Si, by treatment withhexafluorosilicate, SiCl₄, etc. Aluminophosphate molecular sieves alsohave low if any catalytic activity.

Catalytic applications can combine chemical conversion of one or morereactants with in situ separation Such separation may involve, forexample, the separation of one or all of the products from thereactant(s).

For use in a catalytic process, (i) a catalytically inactive membranemay be combined with an active catalyst, or (ii) the membrane itself maybe catalytically active. As an example of the first case (i), a Pt onAl₂ O₃ catalyst is contained in a tubular reactor whose walls consist atleast partly of a catalytically inactive zeolitic membrane chosen toselectively permeate hydrogen.

Dehydrogenation of alkanes is an example of a catalytic process whichmay be accomplished by passing an alkane feed through the tubularreactor; the effluent contains alkene in greater than equilibriumconcentration. In this way, for example, propane may be converted topropylene. In the second case (ii), the zeolitic membrane possessescatalytic activity, either acid activity, or metal activity, or both.The acid activity of siliceous zeolites can be adjusted by the amount ofthree-valent substituents, especially aluminum, by the degree of cationexchange from salt form to hydrogen form or by thermal or steamtreatment. The acid activity of AlPO4 -type zeolites can be increased byincorporation of activating agents such as silica. An example utilizingthe acid activity of the membrane is the dealkylation of ethylbenzene tobenzene and ethylene Utilizing the higher permeation rate of ethylenealone or of ethylene and benzene, a higher degree of dealkylation ingreater selectivity is obtained.

Activity may be correlated with acid character Silicious zeolites may beconsidered to contain SiO₄ -tetrahedra. Substitution by a trivalentelement such as aluminum introduces a negative charge which must bebalanced If this is done by a proton, the material is acidic. The chargemay also be balanced by cation exchange with alkali or alkaline earthmetal cations.

One measure of catalytic activity may be termed the Alpha Value. WhenAlpha Value is examined, it is noted that the Alpha Value is anapproximate indication of the catalytic cracking activity of thecatalyst compared to a standard catalyst and it gives the relative rateconstant (rate of normal hexane conversion per volume of catalyst perunit time). It is based on the activity of silica-alumina crackingcatalyst taken as an Alpha of 1 (Rate Constant=0.016 sec ⁻¹). The AlphaTest is described in U.S. Pat. No. 3,354,078; in the Journal ofCatalysis, Vol. 4, p. 527 (1965); Vol. 6, p. 278 (1966); and Vol. 61, p.395 (1980), each incorporated herein by reference as to thatdescription. The experimental conditions of the test used herein includea constant temperature of 538° C. and a variable flow rate as describedin detail in the Journal of Catalysis, vol. 61, p. 395.

The crystalline membranes of the present invention are readilyconvertible to catalytically active material for a variety of organic,e.g. hydrocarbon, compound conversion processes. Such conversionprocesses include, as non-limiting examples, cracking hydrocarbons withreaction conditions including a temperature of from about 300° C. toabout 700° C., a pressure of from about 0.1 atmosphere (bar) to about 30atmospheres and a weight hourly space velocity of from about 0.1 ⁻¹ toabout 20 hr⁻¹ ; dehydrogenating hydrocarbon compounds with reactionconditions including a temperature of from about 300° C. to about 700°C., a pressure of from about 0.1 atmosphere to about 10 atmospheres anda weight hourly space velocity of from about 0.1 to about 20; convertingparaffins to aromatics with reaction conditions including a temperatureof from about 100° C. to about 700° C., a pressure of from about 0.1atmosphere to about 60 atmospheres, a weight hourly space velocity offrom about 0.5 to about 400 and a hydrogen/hydrocarbon mole ratio offrom about 0 to about 20; converting olefins to aromatics, e.g. benzene,toluene and xylenes, with reaction conditions including a temperature offrom about 100° C. to about 700° C., a pressure of from about 0.1atmosphere to about 60 atmospheres, a weight hourly space velocity offrom about 0.5 to about 400 and a hydrogen/hydrocarbon mole ratio offrom about 0 to about 20; converting alcohols, e.g. methanol, or ethers,e.g. dimethylether, or mixtures thereof to hydrocarbons includingolefins and/or aromatics with reaction conditions including atemperature of from about 275° C. to about 600° C., a pressure of fromabout 0.5 atmosphere to about 50 atmospheres and a liquid hourly spacevelocity of from about 0.5 to about 100; isomerizing xylene feedstockcomponents with reaction conditions including a temperature of fromabout 230° C. to about 510° C., a pressure of from about 3 atmospheresto about 35 atmospheres, a weight hourly space velocity of from about0.1 to about 200 and a hydrogen/hydrocarbon mole ratio of from about 0to about 100; disproportionating toluene with reaction conditionsincluding a temperature of from about 200° C. to about 760° C., apressure of from about atmospheric to about 60 atmospheres and a weighthourly space velocity of from about 0.08 to about 20; alkylatingaromatic hydrocarbons, e.g. benzene and alkylbenzenes in the presence ofan alkylating agent, e.g. olefins, formaldehyde, alkyl halides andalcohols, with reaction conditions including a temperature of from about250° C. to about 500° C., a pressure of from about atmospheric to about200 atmospheres, a weight hourly space velocity of from about 2 to about2000 and an aromatic hydrocarbon/alkylating agent mole ratio of fromabout 1/1 to about 20/1; and transalkylating aromatic hydrocarbons inthe presence of polyalkylaromatic hydrocarbons with reaction conditionsincluding a temperature of from about 340° C. to about 500° C., apressure of from about atmospheric to about 200 atmospheres, a weighthourly space velocity of from about 10 to about 1000 and an aromatichydrocarbon/polyalkylaromatic hydrocarbon mole ratio of from about 1/1to about 16/1.

In general, therefore, catalytic conversion conditions over a catalystcomprising the membrane in active form include a temperature of fromabout l00° C. to about 760° C., a pressure of from about 0.1 atmosphere(bar) to about 200 atmospheres (bar), a weight hourly space velocity offrom about 0.08 hr⁻¹ to about 2000 hr⁻¹ and a hydrogen/organic, e.g.hydrocarbon compound mole ratio of from 0 (no added hydrogen) to about100.

In order to more fully illustrate the nature of the invention and themanner of practicing same, the following examples are presented.

EXAMPLE A

To prepare the initial batch composition, the procedure outlined byHayhurst and Lee (Proceedinqs of the 7th International ZeoliteConference, Murakami, Y., Iijima, A, Ward, I. W., Ed., p. 113, Elsevier,Tokyo, 1986) was followed. The following is a list of the reagents used:Ludox AS-40 (DuPont) aqueous colloidal silica solution as the silicasource, 50% by weight sodium hydroxide solution (Baker, reagent grade),tetrapropylammonium bromide (Aldrich), distilled water.

The tetrapropylammonium bromide, 3.475 gm, was dissolved in 50.0 gmdistilled water by stirring in a polyethylene container. A 0.90 gmquantity of sodium hydroxide solution was added. The resulting solutionwas subsequently diluted with 54.6 gm distilled water. A 37.55 gmquantity of the silica source was slowly added with continuous stirring.About 40 ml of the suspension was poured into a 45 mlpolytetrafluoroethylene (TN) (Teflon) lined autoclave (Parr Model 4744).The molar composition was:

    2.2 Na.sub.2 0:100 SiO.sub.2 :2832 H.sub.2 O:5.22 TPA Br

A polytetrafluoroethylene (TN) slab (80 mm×25 mm×2.5 mm) was immersed inthe solution and placed vertically along the axis of the cylindricalvessel. The autoclave was sealed and placed in a convection oven, whichwas preheated at 180° C.

In a second autoclave, a vycor frit, approximately 1.5 cm in diameter,already mounted inside a pyrex tube (Corning Glass) was immersed in thesynthesis solution.

The autoclaves were removed from the oven after 9 days and quenched withwater. The TN slab was recovered, washed with distilled water and driedat room temperature. The slab and the vycor frit with surrounding pyrextube were observed to be covered with a uniform layer of crystallizedmaterial.

The layer of crystalline material was removed from the TN surfaces bycarefully scraping with a spatula. No solid particles were foundsuspended in the remaining solution or settled on the bottom of thecontainer.

The resulting membranous material was calcined in nitrogen at 560° C.and in air at 600° C. to decompose and burn the organic template. Nocracks generated by the calcination process were observed.

Segments of the zeolite membrane greater than 1 cm² were selected forcharacterization by electron microscopy, X-ray diffraction, Silicon-NMRand hexane sorption. The membrane was crushed to powder form for X-rayand Silicon-NMR tests. It was introduced uncrushed into the sorptionapparatus for hexane sorption measurements.

X-ray Diffraction, Si-NMR and Hexane Sorpion

The X-ray diffraction pattern was shown to be that of pure ZSM-5. TheSi-NMR spectrum, FIG. 1, showed silanols as the only non-ZSM-5 frameworksilicons. Spectra with 30 and 300s relaxation delays were obtained to becertain no dense phases were present. Silanols, whose identity wasestablished by crosspolarization, are seen as a broad peak at about -103ppm. Their concentration is about 1.5 SiOH/unit cell or about 1/3 whatis normally present in a high silica/alumina ZSM-5 made from TPABr. Thehexane sorption capacity, measured at 90° C. and 110.8 torr hexanepartial pressure, was found to be 112.0 mg/gm of zeolite, i.e., slightlyhigher than the sorption capacity of standard small ZSM-5 crystals.

Electron Microscopy

FIG. 2 shows the distinct morphologies of the two membrane surfaces.FIG. 2a corresponds to the membrane surface exposed to the teflonsupport. FIG. 2b corresponds to the surface exposed to the synthesismixture. Although the teflon side surface consists of a layer ofapparently loosely held crystals of less than 0.1 μm size, the solutionsurface consists of a continuous array of densely packed and intergrown(twinned) crystals, 10 to 100 μm in size. The intergrowth is bettershown on the surface of a large single crystal (FIG. 2c). The surface ofthe same crystal at even higher magnification is shown in FIG. 2d. Thisis partly coated with small particles, which may or may not have theZSM-5 microstructure.

The thickness of the membrane was estimated to be about 250 μm.

EXAMPLE B Permeability Measurements

Some permeability properties the membrane of Example A were determinedin a cell, operated in the steady state mode (FIG. 3). sides of themembrane were glued with epoxy resin the perimeter of two Pyrex tubes, 1cm in diameter. The material extending beyond the external surface ofthe tubes was destroyed. A thick layer of epoxy resin was applied theexternal surface of the junction to provide extra mechanical support andeliminate the possibility of gas leaks. The temperature limit or oneepoxy resin used is 120° C. The cell was incorporated in a standard flowapparatus, capable of operating at atmospheric or subatmosphericpressure. The permeability coefficient (P) of a component across themembrane is defined as the ratio of the flux/unit area to the externalconcentration gradient of the component. It is related to theWicke-Kallenbach diffusion coefficient (Dwk) by the expression: P=Kh*Dwk(Matson et al., Chem. Eng. Sci. 38, 503 (1983)) where Kh is the Henry'sLaw constant. This expression is only valid in the Henry's Law regime.It reflects the fact that the true but not directly measurable drivingforce for diffusion, which is the intracrystalline concentrationgradient, differs from the external concentration gradient due to theequilibrium partitioning of the adsorbate established between themembrane surface and the external gas phase (Koresh, et al., J. Chem.Soc., Faraday Trans. 1, 82, 2057 (1986)). For a bicomponent feed stream,the selectivity is defined as the permeability ratio. Except for a fewdata collected at 23° C., permeabilities were measured at 49° C. and 1atm total pressure on both sides of the membrane. The flow rate of thefeed side was 249 cc/min and that of the permeate side was 14.1 cc/min.Helium was used as a carrier ga of the permeate.

Permeability coefficients and selectivities were calculated for threebicomponent gas mixtures:

    ______________________________________                                        Feed #    Composition (mole %)                                                ______________________________________                                        1         21% O.sub.2 /79% N.sub.2                                            2         49.4% H.sub.2 /50.6% CO                                             3         9.5% n-C.sub.6 /16.6% 2,2-DMB/helium balance                                  (normal hexane/2,2-dimethylbutane)                                  ______________________________________                                    

The following permeability coefficients and selectivities weredetermined:

    __________________________________________________________________________         Temp                                                                              Perm. Comp.                                                                          P1     P2                                                     Feed #                                                                             (°C.)                                                                      (mole %)                                                                             (cm.sup.2 /s)                                                                        (cm.sup.2 /s)                                                                        Selectivity                                     __________________________________________________________________________    1    49   .46 ± .01/                                                                       1.31 · 10.sup.-4                                                            1.22 · 10.sup.-4                                                            1.07 ± .05                                            1.62 ± .04                                                        2    23  2.12 ± .05/                                                                       2.63 · 10.sup.-4                                                            1.63 · 10.sup.-4                                                            1.62 ± .04                                            1.36 ± .05                                                        2    49  2.20 ± .02/                                                                       2.59 · 10.sup.-4                                                            1.92 · 10.sup.-4                                                            1.54 ± .01                                            1.48 ± .01                                                        3    49   .335 ± .002/                                                                     1.96 · 10.sup.-4                                                            1.14 · 10.sup.-5                                                            17.2 ± 1.5                                            .0354 ± .0007                                                     __________________________________________________________________________

The data indicate that the composition of the recovery stream differsfrom the composition of the feed stream. The membrane is shown toseparate O₂ and N₂, H₂ and CO, and hexane and 2,2-dimethylbutane. Thisindicates that the zeolitic membrane can discriminate between permeatesat the molecular level. The selectivities observed for the H₂ /CO andhexane/2,2-dimethylbutane feeds strongly suggest that most of thetransport across the membrane takes place in the shape selective poresof the ZSM-5 lattice.

EXAMPLES 1-4

The same synthesis mixture and conditions described in Example A wereused except that the crystallization time was varied.

The thickness of the membranes formed was found to be a function of thecrystallization time as shown in Table 1. It is apparent that longcrystallization times lead to membranes of greater thickness.

                  TABLE 1                                                         ______________________________________                                                 Crystallization Time,                                                                         Membrane Thickness,                                  Example  Days            Microns                                              ______________________________________                                        1        0.3              20                                                  2        1               150                                                  3        2               210                                                  4        4               230                                                  ______________________________________                                    

EXAMPLE 5

Experiment A was repeated except that a 25×25 mm flat silver plate wasused instead of the teflon plate. A ZSM-5 membrane formed on the surfaceof the silver plate.

The silver plate was washed with water and dried at room temperature.The crystallized zeolite membrane could be readily removed from thesupport plate by wetting the surface with acetone at room temperature.

EXAMPLE 6

Example A was repeated using a 25×25 mm flat nickel plate. At the end ofthe crystallization period, the nickel plate was found to be coated witha thin ZSM-5 zeolite membrane.

EXAMPLE 7

Example A was repeated using a flat plate made of #316 stainless steel.Zeolite crystallization again occurred on the surface of the stainlesssteel plate in the form of a thin membrane.

Examples 1-4 illustrate that the thickness of the membrane can beadjusted by varying the crystallization time. This is not intended tomean that the thickness cannot be adjusted in other ways also. Examples5-7 illustrate the use of various types of support plates, however, theinvention is not limited to these.

The following three examples demonstrate further synthesis of membranehaving the structure of ZSM-5.

EXAMPLE 8

The synthesis hydrogel of this example was prepared with the followingcomposition:

A solution was prepared by dissolving 0.78 gm NaAlO₂ and 1.12 gm NaOHpellets into 497.7 gm deionized water. After all of the sodium aluminateand sodium hydroxide had dissolved, 7.98 gm tetrapropylammonium bromidesalt was next dissolved in the basic solution. Finally, 60.0 gmcolloidal sol (30% SiO₂) was added to the basic solution, and the finalsolution was stirred vigorously for two minutes to produce a homogeneoussolution.

The resultant hydrogel is described by the mole ratios:

    ______________________________________                                               H.sub.2 O/SiO.sub.2                                                                    100                                                                  Al.sub.2 O.sub.3 /SiO.sub.2                                                            0.01                                                                 OH.sup.- /SiO.sub.2                                                                    0.10                                                                 Na.sup.+ /SiO.sub.2                                                                    0.12                                                                 TPA.sup.+ /SiO.sub.2                                                                   0.10                                                          ______________________________________                                    

A quantity of the hydrogel was transferred to a one liter stainlesssteel autoclave which held a vertically-mounted teflon strip.

The autoclave was sealed and heating begun immediately. The autoclavewas heated for 3 days at 180° C., without stirring, before quenching theautoclave to room temperature to terminate the crystallization.

After the autoclave was opened and the teflon strip was removed from theremaining liquid, it was observed that crystalline product had depositedupon the teflon surface. This crystalline zeolite membrane wasphysically removed intact from the teflon surface.

EXAMPLE 9

Forty-five milliliters of the hydrogel from Example 8 was transferred toa 65 ml stainless steel autoclave. A teflon strip was mounted verticallywithin the autoclave before the autoclave vessel was capped and sealed.

The 65 ml autoclave was then placed into a convection oven set at 180°C. The autoclave remained in the convention oven at 180° C. (at staticconditions) for 4 days before removal to cool to room temperature.

When the autoclave was opened, it was observed that uniform crystallinedeposit had taken place on the surface of the teflon strip. Thismembrane crystalline zeolite was removed intact from the teflon surface.

EXAMPLE 10

A solution was prepared as described in Example 8, except with aresultant hydrogel composition as follows:

    ______________________________________                                               H.sub.2 O/SiO.sub.2                                                                    29                                                                   Al.sub.2 O.sub.3 /SiO.sub.2                                                            0.0025                                                               OH.sup.- /SiO.sub.2                                                                    0.02                                                                 Na.sup.+ /SiO.sub.2                                                                    0.05                                                                 TPA.sup.+ /SiO.sub.2                                                                   0.05                                                          ______________________________________                                    

The hydrogel was transferred to a 45 ml teflon-lined autoclave, whichheld a vertically-mounted teflon slab.

The autoclave was sealed and placed in a 180° C. oven for 3 days. Theautoclave was quenched, opened and the teflon slab was removed. It wasobserved that crystalline product in the form of a uniformly thick layerhad deposited upon the teflon surface. This crystalline zeolite membranewas physically removed intact from the teflon surface.

Examples 11-18 which follow demonstrate catalytic applications of themembrane composed of molecular sieve.

EXAMPLE 11

A membrane reactor is constructed consisting of a cyclindrical tube of 2cm diameter and 30 cm long with inner walls composed of a membranehaving the structure of ZSM-5. The thickness of the ZSM-5 membrane is 12microns and is supported by a microporous alumina support. The tube isplaced concentrically inside a metal tube of 3 cm inside diametercreating an annulus with a width of about 0.5 cm. Both the insidemembrane tube and the outer annulus are fitted with separate feed andexit lines.

EXAMPLE 12

A membrane reactor assembled as in Example 11 is used with a membranewall composed of ZSM-5 of SiO₂ /Al₂ O₃ ratio >20,000, which isessentially catalytically inactive. Forty ml of HZSM-5 with a SiO₂ /Al₂O₃ ratio of 70 in the form of 1/16 inch extrudates is placed inside theinner tube of the reactor. A feed stream of vaporized cumene with atemperature of 350° C. and 1 atmosphere pressure is passed through thetube at a weight hourly space velocity of 10 hr⁻¹. The reaction productspropylene and benzene are withdrawn in high purity from the annularspace which is swept with a stream of nitrogen.

By comparison, when the same HZSM-5 catalyst is placed in aconventional, non-membrane reactor tube, cumene is converted under theabove conditions to benzene and di- and triisopropylbenzene with onlytraces of propylene.

EXAMPLE 13

A center tube of a membrane reactor assembled as in Example 11 composedof ZSM-5 with a SiO₂ Al₂ O₃ ratio of 700 is filled with a mixture of 10gm molybdenum oxide and 30 gm of quartz particles. Cyclohexane is passedthrough the tube at a temperature of 200° C. and pressure of 25 atm. ata WHSV of 2 hr⁻ 1. Oxygen is passed through the annular tube at a rateof 40 ml per min. The reactor effluent contains cyclohexanone andcyclohexanol in high selectivity with only small amounts of CO₂.

In a conventional non-membrane rector where the oxygen is cofed with thecyclohexane feed, the selectivity to the desired product is considerablylower.

EXAMPLE 14

A center tube of a membrane reactor assembled as in Example 11 composedof ZSM-5 with a SiO₂ Al₂ O₃ ratio of 3000 is impregnated with a solutionof vanadium nitrate in an amount to give 0.5 wt% vanadium metal based ontotal zeolite, and treated with an air stream at 500° C. for 2 hours, todeposit a thin layer of vanadium (V) oxide on the inner surface. Amixture of isobutane and n-butane containing 40% isobutane is passed at220° C. and 25 atm. pressure through the inner tube at WHSV of 2 hr⁻¹,based on the weight of the metal oxide. Air at the same temperature and28 atm. pressure is passed through the annular space. The productscollected from the inner tube product stream contain tertiary-butylalcohol, acetone and trace quantities of CO₂. n-Butane is essentiallyunreacted and is recovered in pure form by simple distillation from theoxygenated products.

EXAMPLE 15

A reactor assembled as is Example 11 is composed of a membrane tubeconsisting of ZSM-5 with SiO₂ /Al₂ O₃ ratio of 220 that has beenconverted to the potassium form. The inner surface of the tube isimpregnated with a solution of chloroplatinic acid in an amount to give0.001 wt% platinum based on total zeolite, and treated in a hydrogenstream at 500° C. for 6 hours, to deposit platinum metal on the innersurface of the membrane tube. Isobutane preheated to 560° C. is passedthrough the tube at 1 atmosphere and converted to isobutene andhydrogen. The latter is withdrawn in high purity from the annularreactor tube.

EXAMPLE 16

Into the membrane reactor of Example 12 is placed a mixture of 10 gm of0.6% Pt on alumina and 20 gm alumina. A stream of isoprene containing 2%of the undesirable linear isomer, 1,3-pentadiene, is passed through theouter annular reactor at 100° C. at a flow rate of 40 gm per hour.Hydrogen in a mole ratio of 0.1 mole hydrogen per mole of hydrocarbon ispassed through both the inner and outer tubes. The effluent consists ofisoprene containing less than 1% of pentadiene and small amounts ofn-pentane.

EXAMPLE 17

The inner tube of the membrane reactor of Example 12 is charged with 40gm of small crystal (less than 0.1 mm) HZSM-5 with a SiO₂ /Al₂ O₃ of 70.A stream of trimethylbenzene and H₂ with a H₂ /HC mole ratio of 2 isconducted at 450° C. through the inner tube at a pressure of 20 atm. anda WHSV of 2 hr⁻¹. A stream of toluene and H₂ in a H₂ /HC mole ratio of2, 450° C., 20 atm. pressure and a WHSV of 1.5 hr⁻¹ is conducted throughthe outer annular reactor space. The effluent from the outer reactorcontains a mixture of toluene and xylenes containing the desiredp-isomer in amounts considerably higher than the equilibriumconcentration of 24%.

EXAMPLE 18

The inner tube of the membrane reactor of Example 12 is charged with 45gm of dealuminized H-mordenite with a SiO₂ /Al₂ O₃ ratio of 15. A streamof trimethylbenzene and hydrogen with a H₂ /HC mole ratio of 2 isconducted through the tube at 330° C. at a WHSV of 3 hr⁻¹ and 30 atm.pressure. A stream of hydrogen (3 moles per mole trimethylbenzene) at apressure of 10 atmospheres is passed through the annular reactor space.The product from the inner tube reactor contains tetramethylbenzene,small amounts of penta- and hexamethylbenzene and xylenes, together withunconverted trimethylbenzene. The product from the outer annular reactorcontains p-xylene, together with small amounts of m- and o-xylene andtoluene.

While there have been described what are presently believed to be thepreferred embodiments of the invention, those skilled in the art willrealize that changes and modifications may be made thereto withoutdeparting from the spirit of the invention, and it is intended to claimall such changes and modifications as fall within the true scope of theinvention.

We claim:
 1. A process for converting feedstock organic compounds toconversion product which comprises contacting said feedstock withcatalyst under catalytic conversion conditions in a reaction zonecontaining catalyst, the reaction zone having walls at least partiallycomprised of a non-composited microporous membrane comprising acontinuous array of crystalline molecular sieve material, with passageof conversion reactants through an inner side of the membrane so that aneffluent emerging from an outer side of the membrane contains at leastone conversion product.
 2. The method of claim 1 wherein the membrane iscatalytically active.
 3. The process of claim 1 the membrane has beenincorporated with a metal function.
 4. The process of claim 3 whereinthe metal is selected from the group consisting of Pd, Pt, Ru, Mo, W,Ni, Fe
 5. The process of claim 1 wherein the membrane ismonocrystalline.
 6. The process of claim 1 wherein the membrane ispolycrystalline.
 7. The process of claim 1 wherein the membrane has adimension of from about 0.1 μ to about 400 μ.
 8. The process of claim 1wherein the membrane has been calcined.
 9. The process of claim 1wherein the membrane has been steamed at a temperature of from about200° C. to about 800° C. for from about 1 to 50 hours.
 10. The processof claim 1 wherein the membrane has been ion exchanged.
 11. The processof claim 10 wherein the ion is an alkali or alkaline earth metal. 12.The process of claim 11 wherein the ion is selected from the groupconsisting of Mg, Ca, Sr, Ba, Na, K, Li, Rb, and Cs.
 13. The process ofclaim 1 wherein the membrane has been deposited with a compound selectedfrom the group consisting of metal oxides, phosphorous compounds,silicon compounds, organic compounds, and coke.
 14. The process of claim1 wherein said molecular sieve material comprises a zeolite.
 15. Theprocess of claim 1 wherein said molecular sieve material comprises analuminophosphate, silicoaluminophosphate, metaloaluminophosphate ormetaloaluminophosphosilicate.
 16. The process of claim 1 wherein saidmolecular sieve material consists essentially of silica.
 17. The processof claim 1 wherein said molecular sieve material has composition interms of mole ratios of oxides as follows:

    X.sub.2 O.sub.3 :(n)YO.sub.2

wherein X is a trivalent element selected from the group consisting ofaluminum, boron, iron and gallium and combinations thereof; Y is atetravalent element selected from the group consisting of silicon,germanium, titanium and combinations thereof; and n is at least about 2.18. The process of claim 17 wherein X comprises aluminum and Y comprisessilicon.
 19. The process of claim 17 wherein n is from about 20 to about10,000.
 20. The process of claim 1 wherein said feedstock compriseshydrocarbon compounds.
 21. The process of claim 1 wherein said organiccompounds comprise oxygenates.
 22. A process for catalytically treatinga hydrocarbon feedstock which comprises contacting a stream of thefeedstock with an upstream face of a catalytically active,non-composited, microporous membrane comprising a continuous array ofcrystalline molecular sieve material, with passage through the membraneunder catalytic conditions so that an effluent emerging from adownstream side of the membrane contains at least one catalysis product.23. The method of claim 1 wherein the membrane is catalyticallyinactive.
 24. The method of claim 1 wherein the feedstock organiccompounds comprises hydrocarbon compounds.
 25. A process forcatalytically treating an organic feedstock which comprises contacting astream of the feedstock with an upstream face of the catalyticallyactive, non-composited, microporous membrane comprising a continuousarray of crystalline molecular sieve material, with passage through themembrane under catalytic conditions so that an effluent emerging from adownstream side of the membrane contains at least one catalysis product.